The invention relates to a guided projectile whose flight path may be modified by controllably exhausting lateral gas jets in the steering planes.
A guided projectile, such as a missile, comprises more especially impeller means, guidance means for measuring the trajectory deviations with respect to the position of the target aimed at and steering means for reducing these deviations so as to minimize its travelling distance at right angles to the target. The control of the flight path of a guided projectile, this term covering more especially missiles, rockets and self-driven devices generally etc., may be achieved by application of a lateral thrust force supplied by jets of material whose flow rate and direction may be modified. A thrust force may be obtained from numerous sources of energy, such as liquid propergols or compressed gases which supply adapted steering means. Whereas these steering means are relatively simple and flexible because they may be activated or deactivated intermittently, without danger for the projectile, they present, to a greater or lesser degree, the disadvantage of excessive weight, a certain sensitivity to temperature and, especially, of being not very easily stored over long periods of time. Therefore, in the guided projectile considered here, the energy source required for directional steering and concurrently for maintaining the flight speed is formed by a solid propergol whose combustion supplies a continuous gas flow. A difficulty inherent in the use of a solid propergol is that once the combustion has been started, it must be maintained at a substantially constant pressure, which involves a gas flowrate which varies within a very small range. In fact, an increase in the flowrate of the gases would lead to extinction of the combustion and conversely a reduction of this flowrate would lead to a prohibitive increase of the combustion pressure with, consequently, explosion of the combustion chamber. Another problem which arises, during design of a guided projectile using gas exhaust nozzles, is to provide for the directions of the elementary thrust forces to converge at a single point advantageously situated in the vicinity of the center of gravity of the projectile.
There is already known, from more particularly French patent application No. 77 10755 filed on Apr. 8, 1977, in the name of the Applicant, a guided projectile in which the flight path is modified by exhausting lateral gas jets. In one embodiment described, corresponding to steering in a single plane, the projectile comprises a gas generator, of the solid propergol type, which supplies a pair of fixed diametrically opposed nozzles. To modify the relative flowrate of the gases passing through these two nozzles, it is proposed to dispose, at the outlet of the gas source and placed in the divergent supply conduits of the two nozzles, a single valve comprising a vane pivoting about an axis, situated on the longitudinal axis of the projectile, perpendicularly to the steering plane containing the two nozzles. The configuration of the means for regulating the relative flowrate of the gas throughflow, particularly adapted to steering in a single plane presents numerous advantages, more especially the flowrate of the gas flow is maintained within very narrow limits, the pivoting vane is balanced by the pressure forces of the gases acting on its lateral faces and the means for positioning the vane are of simple construction.
The aim of the invention is a guided projectile of the above described type in which lateral gas jets may be exhausted in two independent mutually orthogonal planes.